The Institute of Laboratory Animal Resources (ILAR) has, since 1952, sought to promote optimal animal care practices. During the past several years, ILAR has received requests from research institutions and architects relative to criteria for the construction, design, equipment, and maintenance of laboratory animal facilities. Very little definitive information relative to the subject has been published since 1963. In order to update these criteria, the National Academy of Sciences, through ILAR, will assemble a committee of recognized experts (engineers, architects, and laboratory animal care personnel) to assess the current needs for laboratory animal housing criteria, develop a plan for a symposium to be held in the spring of 1976, and to assemble and publish the symposium proceedings.